A software as a service (SaaS) system represents a type that does not have software installed in a computer thereof and receives a software service through the Internet. One of largest features of a SaaS is supporting multiple tenants as compared with the existing installation type software. Supporting the multiple tenants represents that one virtual machine instance supports a service to a plurality of tenants.
Meanwhile, as a SaaS based cloud service is generalized, introduction of the cloud service of an enterprise is actualized, but various efforts for improving the quality of the cloud service are required. For example, when a SaaS provider provides a specialized service to a tenant, since a separate device (appliance) needs to be installed for each tenant in the related art, such inconvenience needs to be solved. Further, in order to solve a problem which occurs as a plurality of SaaS providers provides the service to respective tenants, a proposal of a cloud services brokerage model gathering services provided by the plurality of SaaS providers and providing the gathered services to the tenant is also required.